The invention relates principally to an electronic circuit more especially a circuit capable of working out the discrete Fourier transform calculation.
The Fourier transform is an extremely powerful mathematical tool used more especially for calculating spectra.
The Fourier transform allows the convolution product more particularly to be calculated. In fact, the Fourier transform of the convolution product of two functions is equal to the Fourier transform product of these two functions. Thus, at each point the convolution product of the two functions is equal to the inverse Fourier transform of the product of the Fourier transforms of these two functions.
It is often advantageous to weight a function whose Fourier transform it is desired to calculate. The device of the present invention allows the weighting to be carried out, on order, for example before calculating the Fourier transform. For a discrete succession, weighting is effected by multiplying the terms of the succession by weighting coefficients stored for example in a read only memory (ROM). Advantageously, the ROM contains several sets of coefficients so that the desired weighting may be chosen.